/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.plan.planner.plan.node.process;

import org.apache.iotdb.db.mpp.plan.planner.plan.node.PlanNode;
import org.apache.iotdb.db.mpp.plan.planner.plan.node.PlanNodeId;
import org.apache.iotdb.db.mpp.plan.planner.plan.node.PlanNodeType;
import org.apache.iotdb.db.mpp.plan.planner.plan.node.PlanVisitor;
import org.apache.iotdb.db.mpp.plan.planner.plan.parameter.OrderByParameter;
import org.apache.iotdb.tsfile.utils.ReadWriteIOUtils;

import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;

public class DeviceMergeNode extends MultiChildProcessNode {

    // The result output order, which could sort by device and time.
    // The size of this list is 2 and the first SortItem in this list has higher priority.
    private final OrderByParameter mergeOrderParameter;

    // the list of selected devices
    private final List<String> devices;

    public DeviceMergeNode(
            PlanNodeId id, OrderByParameter mergeOrderParameter, List<String> devices) {
        super(id);
        this.mergeOrderParameter = mergeOrderParameter;
        this.devices = devices;
    }

    public OrderByParameter getMergeOrderParameter() {
        return mergeOrderParameter;
    }

    public List<String> getDevices() {
        return devices;
    }

    @Override
    public PlanNode clone() {
        return new DeviceMergeNode(getPlanNodeId(), getMergeOrderParameter(), getDevices());
    }

    @Override
    public List<String> getOutputColumnNames() {
        return children.stream()
                .map(PlanNode::getOutputColumnNames)
                .flatMap(List::stream)
                .distinct()
                .collect(Collectors.toList());
    }

    @Override
    public <R, C> R accept(PlanVisitor<R, C> visitor, C context) {
        return visitor.visitDeviceMerge(this, context);
    }

    @Override
    protected void serializeAttributes(ByteBuffer byteBuffer) {
        PlanNodeType.DEVICE_MERGE.serialize(byteBuffer);
        mergeOrderParameter.serializeAttributes(byteBuffer);
        ReadWriteIOUtils.write(devices.size(), byteBuffer);
        for (String deviceName : devices) {
            ReadWriteIOUtils.write(deviceName, byteBuffer);
        }
    }

    @Override
    protected void serializeAttributes(DataOutputStream stream) throws IOException {
        PlanNodeType.DEVICE_MERGE.serialize(stream);
        mergeOrderParameter.serializeAttributes(stream);
        ReadWriteIOUtils.write(devices.size(), stream);
        for (String deviceName : devices) {
            ReadWriteIOUtils.write(deviceName, stream);
        }
    }

    public static DeviceMergeNode deserialize(ByteBuffer byteBuffer) {
        OrderByParameter mergeOrderParameter = OrderByParameter.deserialize(byteBuffer);
        int devicesSize = ReadWriteIOUtils.readInt(byteBuffer);
        List<String> devices = new ArrayList<>();
        while (devicesSize > 0) {
            devices.add(ReadWriteIOUtils.readString(byteBuffer));
            devicesSize--;
        }
        PlanNodeId planNodeId = PlanNodeId.deserialize(byteBuffer);
        return new DeviceMergeNode(planNodeId, mergeOrderParameter, devices);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        if (!super.equals(o)) {
            return false;
        }
        DeviceMergeNode that = (DeviceMergeNode) o;
        return Objects.equals(mergeOrderParameter, that.mergeOrderParameter)
                && Objects.equals(devices, that.devices);
    }

    @Override
    public int hashCode() {
        return Objects.hash(super.hashCode(), mergeOrderParameter, devices);
    }

    @Override
    public String toString() {
        return "DeviceMerge-" + this.getPlanNodeId();
    }
}
